1. Technical Field
Embodiments herein relates to electronic devices and methods of forming the same and, more particularly, to semiconductor memory devices and methods of forming the same.
2. Description of Related Art
The integration density of the semiconductor memory devices can be a factor that may influence the cost of the semiconductor memory devices. That is, if the integration density of the semiconductor memory devices increases, the cost of the semiconductor memory devices may be lowered. The integration density of semiconductor memory devices, e.g., planar semiconductor memory devices may be mainly determined by a planar area that a unit memory cell occupies. Accordingly, the integration density of the planar semiconductor memory devices may be affected by, e.g., a technology for forming fine and small patterns. However, realizing fine patterns in the planar semiconductor memory devices may result in increasing manufacturing costs and/or high priced apparatuses. Therefore, there may be some limitations in forming the small and fine patterns.
Recently, three dimensional semiconductor devices including memory cells arranged in a three dimensional array have been proposed to overcome the above limitations.